Reverse battery paystation



Filed May 14. 1953 B I C LINE CKT.

FINDER CONNECTOR Ll 215E CENTRAL OFFICE LOCAL SUB HaoK 5WITCH INVENTOR.

GEORGE KING BY ATTY.

2,820,847 REVERSE BATTERY PAYSTATION George King, Columbia, Mo., assignor to General Telephone Laboratories, Incorporated, a corporation oi Delaware Application May 14, 1953, Serial No; 355,013

4 Claims. (Cl. 179-63) The present invention relates in general to telephone paystations and more specifically to paystation circuits and apparatus particularly adaptable for use with telephone paystations more commonly known as the reverse battery type.

The primary object of my invention is to provide simple, economical and improved reverse battery paystation apparatus and a circuit for use therewith, whereby talking connections between a calling paystation and a called subscriber are established in an efficient, reliable and satisfactory manner.

Another object of the invention is to provide an improved reverse battery paystation, whereby the time required to complete the above-mentioned connection is appreciably reduced with respect to the amount of time required by the other known types now in use.

Referring to U. S. Patent 1,383,472, issued July 5, 1921 to G. A Long, it will be noted that this patent may be taken as one disclosure of a standard automatic paystation telephone showing the normal equipment therein and requiring the deposit of a coin of a certain denomination as the usual established fee charged for all local calls. This standard paystation telephone has individual thereto the conventional coin chute, coin hopper, coin trigger, polarized relay, contactfmechanism associated with the coin trigger and relay, receiver, transmitter and coin operated signal.

When the above-mentioned standard paystation is used as a reverse battery type, the circuit and apparatus thereof is modified to meet the necessary requirements in which, after a call has been initiated and responsive to reverse battery being received by the paystation when the called party answers, the winding of the polarized relay is energized in one direction, whereby the relay operates certain contacts associated with the coin trigger and which shunt the transmitter. Other contacts are operated by the relay at this time which normally prepare an energizing circuit in the other direction. for the relay. A deposited coin then operates the coin trigger contacts to remove the transmitter shunt and deenergize the relay. After conversation is completed and when both parties restore their receivers, the battery is restored to. normal polarity andfat this time the relay is energized in the other direction to reoperate the relay for restoring the coin trigger contacts and all other contacts to normal. it will be obvious that the polarized relay is highly sensitive and very critical in adjustment and operation. Additionally, the manufacturing cost of a polarized relay is relatively high when compared with that of a standard relay In accordance with the main feature of my invention, means is provided at the paystation telephone whereby the standard polarized relay is eliminated;

Another feature of the invention relates to the inclusion of a rectifier in the paystation circuit for shunting the transmitter until the proper fee has-been deposited.

Another feature of the invention relates to the pro- 2 vision of a series relay in the paystation circuit and which is normally energized when a call is initiated and is then released by the above-mentioned rectifier shunt for preventing use of the receiver until the proper fee has been deposited.

An additional feature of the invention relates to the provision of a control relay in the paystation circuit and which is energized in response to a deposited coin operating the coin trigger contacts for removing the above-mentioned shunts from the transmitter and series relay in order for conversation to take place. 7

A further feature of the invention is the inclusion of a normally deenergized release relay in the paystation circuit responsive to the operation of the abovementioned control relay and is energized when a call is completed for releasing the control relay and restoring its associated contacts to normal.

Another feature of the invention is the provision of mechanical linkage means in the paystation common to both the control relay and release relay and which is operated by the control relay to lock itself operated and then reoperated by the release relay for releasing the control relay.

An additional feature of the invention is the provision of means in the paystation circuit, whereby coins may be deposited after a call has been initiated by the paystation, but before the called party answers, so that the talking connection is completed in much less time than was previously required in a reverse battery paystation system.

These and other objects and features of the invention will become apparent upon a further perusal of the specification and claims taken in conjunction with the accompanying drawings, which show by means of the usual diagrams a sufficient amount of the apparatus to enable the invention to be described and understood and in which:

Fig. l discloses the invention as used in a modified reverse battery paystation in detail, and showing associated therewith, the line circuit, finder, connector, local subscriber and central office represented in block diagram and with means shown in the connector for reversing battery to the connection when a call is answered by a local subscriber.

Fig. 2 is a schematic representation showing how the contacts of the control relay may be locked in an operated position when the relay is operated, and how the release relay may unlock the arrangement in order for them to restore.

in its preferred form, such as disclosed in the present application, the objects and features are accomplished as briefly described hereafter. The apparatus included in the previously mentioned standard paystation telephone is modified by removing the polarized relay and substituting in its place a pair-of standard type relays; A single armature, common to both relays, is provided and is operated and caused to remain in one'position by one relay to hold its associated contacts operated. The armature is operated by the other relay to the opposite position where it is caused to remain for restoring the operated contacts of the first relay to normal. A third relay is included in series in the line circuit and the paystation circuit is further modified to include a rectifier therein.

When an outgoing call is initiated from the paystation telephone and r=3ponsive to tie loop circuit con pleted, the third mentioned relay (hereafter designated as a series relay) is energized and operates. A signalling connection is established'responsive to dialling and reverse battery is applied to the connection when the called party answers. Upon receipt of reverse battery,

the rectifier" functions in a finder are taken into use in a Well-known manner.

soon as the loop circuit is established, series relay operates over a well-known circuit which. may be traced 3 well-known manner to shunt the transmitter and series relay. The series relay thereby restores and in so doing, shunts the receiver. Conversation between thecallingand called parties is thus prevented'until a coin isideposited. When a coinis deposited, the coin trigger is momentarily operated, which operates. contacts Y to 5 momentarily remove 'a normally: ef-, fective shunt'from around thefirst relay (hereafter desig natedas a control relay) of the pair, whichimmediately operates. The control relay operates .the common arma.

ture in oneudirection, whichoperates associated contacts and also 'remainsin this operated position. At one set off contacts: the circuitior' thefrectifier 'is opened, at an other set of, contacts the. second'relay. (hereafter designa d; as-a 'r'elease'relay)' .is connectedin parallel with the co trolfrelay and the control relay also hpens its own shuntin'g'circuifl The opening of the circuit to the rectifi'er'allows current tofiow thr ough'Ithe transmitter and also .reenergizes the series relay, which operates to remove the shunt from the receiver... Conversation is thereby allowed: to proceed. At' the end of conversation and after the calling party hangs up, the hook-switch springs are opened to open the" circuit of the control relay and remove the release relay from its aforementioned parallel connection. This relay is momentarily energized to operate the common armature and cause it to stay put in a difierent position, this releases the control relay contacts to thereby clear the line for the next call.

-When there is a toll call, special service or incoming cell, battery is not reversed, whereby the rectifier does not function and the series relay remains operated so that conversation may proceed immediately.

It will beappreciated that the party at a calling paystation may. deposit the required feeimmediately after dialling butrbefore the battery reversal when the called.

party answers. In this case, the control relay operates and opens the circuit to the rectifier and the series relay remains operated. Conversation may thus proceed as soon as the called party answers, thereby saving con 'siderable time and also aiding in preventing the called party fromhanging up, which could take place during the time that'conversation is normally blocked and while the depositis being made because the called party is not always aware that the call has originated from a paystation. a a I Having briefly described the invention, a detailed def scription willffollow. Referring to the drawings and assuming that the paystation such as shown in the upper portion of Fig. 1 desires to make a call to a party at the local subscribers station represented by the block diagram in thelower section of Fig. '1, the following opera- 'tions will take place.

When the party at the calling paystation removes his receiver, the hook-switch closes its associated contacts --17 (as shown) and the illustrated line circuit and As from one winding of the line relay (not shown) in the line circuit, line conductor L1, contacts 32, coin trigger contact 25, hook-switch contact 17, impulsing contact of dial 1, contact 11, resistance 9, winding of" relay 10, transmitter 3, coin transmitter 4 and out over line conductor L2 to the other winding of the line relay in the line circuit. 7 p V -'--In operating contact 11 at this time, series relay 10 removes resistance 9 from around the winding 8 of the induction coil. This frees receiver 2 for use by the calling. paystation.

Upon receipt of dialtone, the calling party operates dial 110 establish a signalling connection with the de: sired local subscriber in a well-known manner. It should be noted that series relay .10 may follow the impulses transmitted from dial 1 during the time that the call numberis dialled, with no apparent etfect. and at the end of dialling will be in its operated position as'previously described. a Y I i i Before continuing further with the present description, it is thought best to describe more in detail the battery reversing operation of the connector represented, in the drawing in block diagram, The connector may be of any well-known type adaptable for use with a telephone system having reverseebattery operated paystations included therein. While theblock diagram representing the connect'or shows only the line conductors L1, L27,"

the line'relay 202 and the battery reversing back-bridge relay 201, it is assumed that when a call is initiated at'the paystation, the line-conductors L1 and Lz otthe paystation are connected through the line circuit, finder and to the line conductors L l -aandL2'; respectively, of-the, connector in a well-known manner. These line conductors are shown as being able to be extended by the connector to the switch boardin the centralofiice or to the telephone of aflocalsubs criber. The switch-hoolccontacts of the local telephone are shown open, which means that thereceiver is in place. Howeven'it is obvious that upon answering an incoming call by removing .the re ceiver, the switch-hook contacts closeto cause the bat tery' reversing operation. 'Connectors having line and to hold the contacts of relay30 operated independent of back b'ridgerelays such as 201 and 292 are well-known; for instancefin the U. S. Patent 1,889,229, granted No vember 29, 1932, toV.'S."Tharp, it will be seen that'th connector disclosed in Fig. v2 therein has facilities for use with, a telephone system wherein 'paystation's of the reverse battery type are served. vReterring'in particular to pages 78 o'f the above-mentioned Tharp patent,@ and I lines 130. and 1940; respectively, it will be noted; that a detailed operationalde'scription of the connector-isgiven when the party onthe called line answers thee'stablishe'd signalling connection and thereversal' of-battery takes place. In order to establish an easier identification, applicant'vhas [used the same reference. characters in the connectori of the above-mentioned patent. 7

Upon receipt of the incoming signalfthe party at the called 'local sta'tionremoves his rece'iverand the associ'-: ated connector. is operated to reverse the connectionsof battery to the connection in the manner such as described in the abovementione'd reference patent. i a t Rectifier -'R1 inthe paystation circuit functions ;in a well-known manner juponreceipt of reverse battery and passes current to cause transmitter. 3 a'ndseries relay 10 to beshunted out. This shunting circuit may be traced asv follows]: from a certain pole of battery in the connector, finder, line circuit, line conductor L2, coin transmitter 4, rectifier. R1, contact33, winding 8 of the induction coil, impulsing spring of dial 1, hook-switch contact 1'], coin trigger contact 25,contact 32,-line conductor L1 and back overthe connection to the opposite pole of battery in the connector.

In restoring contact 1 1,v series relay 10 connects re sister .9 across th e induction coil winding 8, thereby shunting receiver At this time neither receiver 2 nor transmitter 3 can be used andconversation is prevented until a coin is deposited by the calling partytoi'estab lish the talking connection.

g The deposit of the required coin by the calling sub-' scriber momentarily'operates the coin trigger, which in turn momentarily opens contact25. The opening of contact 25 removes the short from across the winding of control relay 30, and this relay will be energized over the previously tracedfcircuit; Controlrelay 30 operates the common armature '18 which remains in this'position the energization of relay 30. 7

It is thought best atltlii s time to mention again that armature 18 is' operated in two-separate movements by relays 30 and-20 and is-so arranged when operated by relay 30, 'to'remain inithat operatedpo'siti0n to'hold the contacts of..control relay"30 operated in any well-known mannerrsuch'asishowniinFig. 2.". Armature18iis subsequent'ly operated to its opposite positicn by release relay 20 and now remains in its newly operated position to release the contacts of relay 30 and restore them to normal.

In operating contact 31-, control relay 30 connects release relay 20 in parallel with itself. However relay 20 does not operate at this time due to the low resistance shunt including relay 30. At contact 32, the former shorting circuit of control relay 3% is opened and at contact 33 the circuit of rectifier R1 is Opened. Since rectifier R1 is no longer in shunt of relay 10, the formertraced energizing circuit for series relay is reestablished and transmitter 3 is included in the circuit; In Operating contact 11, series relay I0 removes the shunt from induction coil winding 8, and receiver 2 is also rendered effective.

Conversation may now take place in the usual manner.

At the end of conversation and responsive to the calling party replacing his receiver, hook-switch contacts 16 and 17 open and contactiS closes. The operation of book switch contacts and 16 have no apparent effect at this time, however contact 17 now excludes release relay 20 from its previously mentioned parallel connection with control relay 30. Release relay 20 is now momentarily energized over the previously traced circuit including line conductor L2 and up to and including the pulsing con tacts of dial 1, then to the right through the winding of relay 20, contact 31 and out to the connection over line conductor L1. In operating common armature 18, relay 20 unlocks control relay 3%) and restores its contacts to normal, whereby the line is cleared for future calls.

In the event that a toll call or a special service call is initiated by a calling party at the paystation, the equip ment is operated as just described up to and including the point that the call is answered. The answering of this type of call by the toll operator does not cause reverse 'battery to be applied to the connection, therefore rectifier R1 does not function to shunt transmitter 3 and series relay 10, so that the conversation with the operator may proceed immediately since both receiver 2 and transmitter 3 are energized and included in the circuit. When the toll call is established, the paystation deposits the requir'ed toll fee and the operator completes the necessary operation in order for conversation to be had with the desired party. The equipment will also function in like manner for incoming calls to the paystation.

It will be appreciated that the paystation users may deposit the required fee on all outgoing local calls immediately after dialling the desired call number and be fore the called party answers, whereby considerable time is saved, since conversation may proceed immediately upon answering. Also, when compared with the procedure of handling the standard reverse battery paystation call, considerable confusion may be avoided at the called station for the reason that when an incoming call from a reverse battery paystation is answered by the local party in the previous type of system, conversation can not take place until the calling party has deposited the necessary fee and the called party upon being unable to detect any one on the line at that moment may hang up before the deposited coin has established the talking connection. Referring to the occasion when the calling party has deposited the coin before the called party answers, the equipment operates in the same manner as previously described for the local call up to and including the establishing of a signalling connection responsive to dialling. At this time the calling party may deposit the required fee, whereupon the deposited coin operates the coin trigger contact 25, which in turn completes the previously described energizing circuit for control relay 30. Control relay operates over the closed loop circuit previously described for the operation of relay 1G. The receipt of reverse battery at the paystation when the called party answers will not affect control relay 30. However, when reverse battery is received at the pay- '6 station, the shunt including rectifier R1 is not effective and series relay lll'does not restore since contact 33 is opened. Both receiver 2 and transmitter 3 are now-effectively included in the circuit and conversation may pro c'e'ed at once. After conversation the equipment restores in the same manner 'as'previously described.

Having described my invention and what is considered new and desired to have protected by Letters Patent will be pointed out in the appended claims.

What is claimed is:

1. In a telephone system, a line having a paystation thereon, 21 called subscriber, a substation circuit including an induction coil, a transmitter, a relay, normally closed contacts controlled by said relay, a receiver circuit com prising a primary winding and a receiver bridged across a secondary winding of said induction coil, a first normal- 1y closed shunt circuit comprising said contacts shunting said primary winding thereby causing said receiver circuit to become ineffective, means responsive to the initiation of a call on'said line for initially operating said relay over said first shunt circuit and the line conductors of said line, means for extending a connection from said paystation line to said called subscriber, means for reversing battery over said line when said connection is answered by said called subscriber for momentarily energizing said receiver circuit, a second shunt circuit comprising a rectiheiconnected in bridge of said relay and said transmitter effective in response to the receipt of reverse battery to cause said transmitter to become ineifective and to restore said relay, said contacts restored to normal by said relay to reclose said first shunt circuit to again cause said receiver circuit to become ineffective, and means responsive to the deposit of a coin for opening said second shunt circuit to cause said transmitter to become effective and to reope'rate said'rela'y, said contacts reoperated by said relay to open saidfirst shunt circuit to cause said receiver circuit toagain become effective, whereby conversation is free to take place over said connection.

2. In a telephone system, a line having a paystation thereon, :1 called subscriber, a substation circuit for said paystation, an induction coil in said circuit having a primary winding and secondary windings, a receiver bridged across one of said secondary windings; a first normal current path in said substation circuit comprising a transmitter, a relay and said primary winding connected in series; a second normal current path in said substation circuit comprising said transmitter and said relay connected in series and a normally closed shunt circuit shunting said primary winding to exclude said receiver from said substation circuit, means responsive to the initiation of a call by said paystation for completing said second normal current path to energize said relay, contacts included in said second normal current path operated by said operated relay for opening said second normal current path to both maintain said relay operated and to open said normally closed shunt circuit and operatively include said receiver in said substation circuit by way of said first normal current path, means for extending a signalling connection from said paystation line to said called subscriber, means for applying reverse battery current to said paystation line when said connection is answered by said called subscriber, a rectifier connected in shunt of said relay and said transmitter, a first reverse current path in said substation circuit comprising said rectifier and said primary winding connected in series rendered conductive responsive to receipt of said reverse battery current to shunt said relay and said transmitter, whereby said series relay is restored and said transmitter is excluded from said substation circuit, a by-pass circuit comprising said rectifier completed responsive to the restoration of said contacts by said restored relay for shunting said primary winding to again exclude said re ceiver from said substation circuit, a coin operable device at said paystation, means operated responsive to the operation of said coin device by a deposited coin for ,7 excluding said' rectifier from said first reverse, current pathand from said by-pass circuit, whereby said second normal current pathis thereafter rendered conductive to the passage of said reverse battery current to re-energize said relay and operatively include said transmitter in said;

substation circuit, said contacts being reoperated by said operated relay to open said second normal current path and render said first normal current path conductive to said reverse battery current for including said receiver in said substation circuit to enable conversation to take place over said connection.

3. In a telephone system, a line having a paystation thereon, a called subscriber line, a substation circuit, an induction coil having a primary winding and secondary windings, a receiver circuit comprising said primary winding and a receiver bridged across one of said secondary windings; a first current path in said substation circuit comprising a transmitter, a relay and said primary winding connected in series; a second current path in said substation circuitcomprising said transmitter and said relay connected in series and a normally closed shunt circuit shunting said primary winding to render said receiver circuit ineifective, means responsive to the initiation of a call on said line for initially operating said relay over said second current path; contacts included in said second current path operated by said relay for opening said second current path to both maintain said relay operated and to remove said shunt on said primary winding and render said receiver circuit effective over said first current path; means for'establishing a signalling connection from said paystation line to said called line, means for applying reverse battery current to said paystation line at the time said connection is answered by said called subscriber, a shunting circuit including a rectifier conductive only upon receipt of said reverse current flow by said substation circuit connected in shunt of said relay and said transmitter, a coin operable'device at said paystation, and means controlled responsive to the operation of said coin device by the deposit of a coin before said connection is answered by said called subscriber for opening said shunting circuit to render said first current path conductive to the said flow of said reverse battery current responsive to said called line answering said tion, means in said switching apparatus forsignalling said called station, means in said switching apparatus controlled in response to the answer of said call at said called c station for reversing the direction of normal current fiow over said two conductor line at said calling station; a'first circuit completed in response to the initiation of said connection including said line conductors, said relay, and said transmitter in series for operating said relay; contacts controlled in response to said operation ofsaid relay for interrupting said first circuit and completing a second circuit including said line conductors, one wind-' ing of said induction coil, said relay, and said transmitter in order to maintain said relay in its operated condition and to inductively couple said receiver through another winding of said'induction coil to said second circuit; a third circuit including said rectifier for normally shunting said transmitter in order to prevent it from transmitting signals over said line conductors after said current flow is reversed in said line conductors, and means responsive to the deposit of the appropriate coinseither before or after said call'is answered at said called station for removing said shunt from said transmitter in order to render the same efifective to transmit signals over said line conductors.

References Citedin the file of this patent- UNITED STATES PATENTS 2,073,508 Williams Mar. 9, 1937 2,133,523 'Alexandersson et al. Oct. 18,1938 2,137,409 Martin et a1. Nov; 22, 1938 2,214,245 Evers Sept. 10,1940 2,217,041 Boswau Oct. 8, 1940 2,281,062

Brubaker Apr. 28,. 1942 

